In a device with a fingerprint sensor, a fingerprint sensor may be used to authenticate a user. An authentication process may enable access to data or functions not otherwise available to an unauthorized user.
The fingerprint sensor may reside, for example, underneath a touchscreen and capable of sensing touch on the entire screen. The fingerprint sensor may also reside only under a portion of a touchscreen. The fingerprint sensor may also reside at the back, or sides, or on a button of a device. The fingerprint sensor may be operatively coupled to other components in a device, such as a processor or a touchscreen. The fingerprint sensor may also be integrated with, or function as, the touch screen of a device.
In conventional devices with fingerprint sensors, a user places their finger on the fingerprint sensor and their fingerprint is authenticated once and then is able to access certain data or functions of the device. Typically, the device provides a timeout function for disabling access once the device has not been interacted with for a period of time. After the device times out, a user must reauthenticate in order to access certain data or functions.
The timeout period may be adjustable by a user, and, for example, a user desiring to not frequently authenticate may set the timeout period to 10 minutes or more.
One disadvantage of this technique is that a user may be authenticated with a device, and a second, unauthorized user, may access the device as if they were the authorized user as long as they do so before the device times out.
One solution to the aforementioned disadvantage is to continually authenticate the fingerprint of the user as they use the device. However, the downside to continuous authentication is twofold—it consumes more power and, because a full fingerprint authentication process has an associated latency, it may negatively impact user experience.
Therefore there exists a need for a power efficient, low-latency authentication process which provides additional security over a process which relies on a timeout.